2. "Fats in your food will make you fatter." Since the 1970s, the food industry has demonised fats. This also coincides with the "fat free" movement, as well as the start of the developed world's obesity and diabetes epidemic. Small and regular amounts of both saturated and unsaturated fats are, in fact, helpful in reducing your overall body fat. Fat deposition and hunger are governed by a complex set of hormones with names like leptin and ghrelin. Simply put, when your body is not getting the amount of fat it expects from your diet, it will respond by making more and holding on to it since it thinks you are starving. So try and stick to a good ratio of fats like omega-3s and fish oil. Remember low fat DOES NOT necessarily mean LOW CALORIES! Your usual salad dressings and sauces that say low fat are, in fact, high in sugar. It's better to go for the normal "more fat" version and just restrict the quantity you have. 3. "A calorie is just a calorie." 1 gram of carbohydrates will get you about 4 calories. A gram of protein is about the same and a gram of fat yields a whopping 9 calories. The old logic goes: by filling up on more proteins and carbs, you would have less calories overall, since the carbs and proteins yield less calories. This kind of logic totally ignores the fascinating way your body interprets and deals with these individual nutrients.